Time and Frequency Domain Responses
Time-domain reflectometry (TDR) is used to characterize interconnections in the time domain. The setup essentially consists of a time domain step generator and a digital sampling oscilloscope. Measuring the reflected signal is called TDR; the transmitted signal is measured using the time-domain transmission (TDT) option. The Characteristic impedance levels and delay through an interconnection structure can be derived from the TDR measurements. The TDT measurement gives information about the losses and degradation of the rise time. The TDR/TDT measurements are used to extract an equivalent circuit consisting of transmission lines and lumped elements. One of the advantages of TDR is its ability to determine impedance levels and delays through an interconnection structure with multiple discontinuities. The network analyzer measurement errors can be classified in two categories: random errors and systematic errors. In most S-parameters measurements, the systematic errors are those that produce the most significant measurement uncertainty.